Alongside Switzerland's Celtic Frost and Sweden's Bathory, Germany's Helloween were possibly the most influential heavy metal band to come out of Europe during the 1980s. By taking the hard-riffing and minor-key melodies handed down from metal masters like Judas Priest and Iron Maiden, then infusing them with the speed and energy introduced by the burgeoning thrash metal movement, Helloween crystallized the sonic ingredients of what is now known as power metal. Sadly, just as they were on the verge of breaking to a wider audience -- even flirting with American success -- the band's meteoric rise was rudely interrupted by internal strife and a string of bad business decisions. These blunders kept them from ever regaining their original momentum, but Helloween took their hard-knock lessons in stride and continued to prosper in the international metal arena on their own terms. More importantly, they remained the benchmark by which most every power metal band is still measured.